Millions of Americans suffer from the debilitating disease of temporomandibular joint (TMJ) disorder, affecting their ability to eat, talk and live their lives. For the patients whose joints do not respond to basic treatments and continue to have long term problems, a doctor may recommend to perform surgical procedures to correct underlying problems in the joint. The last form of treatment available is the surgical replacement of the entire joint with an implanted prosthesis. Often the patient that receives this final recommendation has endured years of suffering and many forms of partial treatment of the problem; frequenting many different doctors from different fields, such as neurosurgeons, rheumatologists, and dental surgeons. Current guidance from the NIH suggests that all forms of treatment be exhausted before resorting to a non-reversible surgical treatment; the total joint replacement being the treatment of last resort. There are a large number of people for whom this final treatment is necessary but doctors are reluctant to recommend that the surgery be performed. Vista Engineering and the University of Alabama at Birmingham (UAB) have been developing a next generation diamond surfaced TMJ prosthesis implant in an attempt to revolutionize this market. This device is less invasive, with a reduced surgical procedure, and greater biocompatibility. The very nature of the device is innovative in that it is not a total joit replacement device, but a resurfacing device where the majority of the existing joint is retained including all the joint stabilizing muscles. The proposed research is innovative because an animal model for the TMJ has not been proven. Furthermore, the long term viability of diamond surfaces for implants is not well studied. The proposed research will evaluate the performance of the UAB-Vista diamond surfaced TMJ at the conclusion of a 12-month animal trial involving 28 diamond surfaced implants in 7 miniature pigs plus a control device in an eighth. The surgeon will examine the tissue and health of the TMJ prior to extraction. Research on the explant devices will focus on the integration of the bone to the implant and a search for evidence of giant cell foreign body (GCFB) reactions. The integrity of the diamond surfaces, indications of articulation behavior and the fixation of the device to the bone will be determined through laboratory investigations.